Process of hardening steel



(No Model.)

G. P. SIMONDS. PROCESS OF HARDENING STEEL.

No. 466,442. Patented Jan. 5, 1892.

mum, WASHINGTON n c UNITED STATES PATENT OFFICE.

GEORGE F. SIMONDS, OF FITCHBURG, MASSACHUSETTS.

PROCESS OF HARDENING STEEL.

SPECIFICATION forming part of Letters Patent No. 466,442, dated January5, 1892. Application filed August 22, 1891. Serial No. 403,459. (Nomodel.)

To all whom zit may concern.-

Be it known that LGEoReE F.S1MoNDs, of

'Fitchburg, in the county of Worcester and State of Massachusetts, haveinvented a new and useful Improvement in Processes of Hard ening Steel,of which the following, taken in connection with the accompanyingdrawings, is a specification. V

This invention relates to processes of hardening steel.

The purpose of the invention is to.harden steel Without subjecting it toundue and unequal, strains in the process of cooling, thus avoidingfracture and warping of the parts.

The purpose of the invention is also to improve the quality of articlestreated.

To enable others skilled in the art to make and use my invention,I willproceed to describe the same in connection with the accompaiiyingdrawings, in which I have illustrated one form of apparatus by whichsaid invention may be practiced.

In the said drawings, Figure l is a perspective View of a box containingthe bath in which the articles are cooled, and Fig. 2 is a per spectiveof a wire basket by which the treated articles are handled when thisbath is used.

In Fig. 1, A is a box or tank, the inside of which is divided into twocompartments B O by thepartition D, which extends about twothirds of thedistance from the top to the bottom of the box, thereby forming at thebottom of the box an open communication between the compartments B O.

E is a sight-opening in the box in the front side of compartment B,provided with glass, for the purpose of observing the line ofdemarcation between the brine and the oil floating upon itin compartmentB. As the specific gravity of oil is less than that of brine, with thisapparatus I am able to keep the compartment 0 nearly full of brine andcompartment B full to a line above the bottom of partition I), with sucha depth of oil on top of the brine in compartment B as may be desired,for purposes hereinafter specified, the brine in both compartments andthe supernatant oil in the said compartment 13 being indicated in Fig.1.

It is often desirable in hardening steelto cool the article treated withgreat rapidity to make it veryhard and then complete the process bycooling more slowly to prevent quick and uneven contraction andfractures. This is sometimes done by cooling in a vat of brine and thentransferring the partially-cooled article through air into a basin ofoil; but this method is very objectionable, as the good effects of theprocess of cooling, first in brine and then in oil, are greatlydiminished by the interruption of the process by the transfer throughthe air or some other intermediate medium in passing from the brine tothe oil.

To obviate this ditficulty I proceed as follows: The basket, H (shown inFig. 2,) formed of wire and provided with a vertical handle H, risingfrom one of its sides, is passed down through the oil and into the brinein compartment B, as shown in Fig. 1, with the handle B of the basketstanding in close proximity to the outer end of the compartment, asshown inFig. 1. The basket, which rests upon the bottom, is then movedunder partition D, so as to rest on the bottom of compartment 0, inwhich position it will substantially fillv the bottom of the compartment0, with its handle rising close to the partition D, as indicated by fulllines in Fig. 1. The heated articles to be hardened are then droppedinto the basket in the brine, and the basket is removed to compartmentB' and lifted up through the brine into the oil floating upon thesurface of the brine, where the process of hardening is completed. Thearticles are allowed to cool in the brine or in the oil for such time asmay be desired to produce the best results, according to thecircumstances of each case. By these means the process of tempering iscompleted Without any interruption, as the articles under treatment areremoved from the brine into the oil without exposure to the atmosphereor other intermediate medium. By this mode of procedure markedeconomical advantages are derived by obviating the risk of warping andbreaking, and remarkable improvements are obtained in the quality ofarticles hardened.

I may carry on the process continuously by means of apparatus actuatedby suitable power and having an especial adaptation to the practice ofmy invention; but as this appartus forms the subject-matter of aseparate concurrent application filed by me of even date herewith nodescription thereof is neccessary in this specification.

It will be understood that I do not confine myself strictly to brine andoil, as other quick and slow cooling liquids of diiferent specificgravity may be substituted in the process.-

I-Iaving thus described my invention, what I claim is- 1. The process ofhardening steel, consisting in plunging the heated article into brineand transferring it from the brine directly into oil Withoutintermediate exposure, substantially as set forth.

2. The process of hardening articles of steel, consisting in plungingsaid articles into a

